Bulletin d’avalanche

Purcells

Apr 16 – 17, 2013Avalanche Canada
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Archivé · expiré 13 years ago

Danger d’avalanche

Thu
Fri
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Points saillants

This bulletin was produced using limited data. Significant variations in snowpack structure are likely to exist. If you've been traveling in the backcountry, we'd love to hear from you at [email protected].

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–4
    Wind slabs exist on a variety of aspects at treeline and above. Wind has also formed very large and potentially unstable cornices.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    1–6
    A weak interface buried in the upper metre of the snowpack can create surprisingly large avalanches. It's been reactive in nearby regions, but there's limited information about its reactivity in the Purcells. Be cautious in alpine terrain.

Confidence

Fair - Timing, track, or intensity of incoming weather is uncertain on Thursday

Weather Forecast

Wednesday: Light snow. Light W winds. Freezing level near 1600 m.Thursday: Trace amounts of snow possible. Light W winds. Freezing level near 1800 m.Friday:  Light snow. Light W winds. Freezing level 1900 m.

Avalanche Summary

Explosives triggered several size 2.5-3 slabs on northerly aspects above 2600 m on Monday. The largest failed a metre deep. On Sunday, a naturally triggered size 2.5 slab failed on a buried crust. Numerous small loose dry avalanches were also observed. In neighbouring Glacier National Park, skiers triggered a size 3 slab on a buried crust on an east aspect in the alpine on Monday. The slab above this interface may be reaching tipping point with incremental loading from snow and wind.

Snowpack Summary

Up to 40 cm recent storm snow has been shifted by variable winds into wind slabs at treeline and above.A weak interface down about 60-120 cm consists of a crust on solar aspects, and surface hoar on high-elevation northerly aspects. Cornices in the region are very large and potentially destructive. Periods of warming or solar radiation may increase the reactivity of cornices and storm slabs.

Régions couvertes